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382                          THE AMAZONIAN DOLPHIN                         CHAP.
those of terrestrial mammals; i.e. the humerus is distinctly the
longer, the converse usually obtaining among Whales. But
Platanista, again agrees with Inia. The teeth are remarkable
for the fact that the hinder-most ones of the series have an
additional lobe; they are not purely conical as are those of
Whales generally.
There is but one species, Inia geoffirensis, which inhabits the
Amazons, and grows to a length of 8 feet. Its colour
variations are rather extraordinary, unless they can be set down
to sex, which has been denied. Some individuals are wholly
pink; others are black above and pink beneath. This Whale is
believed by the Indians to attack a man in the water, and it is
added that the Botalia of the same streams will defend him from,
these attacks! ^Naturally, therefore, superstitious reverence
attaches to this Dolphin, which is tiresome to the naturalist who
wants specimens, as Professor Louis Agassiz found.
In the genus Pontoporia * the dorsal fin is well developed
and falcate. The teeth are very numerous, 200 in all The
ribs articulate as in Dolphins. The skull closely resembles that
of Inia, and the scapula is, as in that genus, " normal."
The proper name for Pontoporia is really Stenodelpliis, which
name was first used by G-ervais a month or two before Gray, who
separated it from the vague Ddphinus of its original discoverer,
Gervais himself. It has a longer snout than Inia, which, being
bent towards the extremity in a downward direction, curiously
suggests the skull of a Curlew. In details, however, the skull is
exceedingly like that of Inia. It is nearly symmetrical. The
vertebral formula appears to be the following:C 7, D 10, L 5,
Cu 20 = 42, just one over the number of the vertebrae in
Inia, The sternum is in two pieces. Of the ten pairs of
ribs the first three are double-headed. These and the next have
sternal moieties joining the sternum, of which the first three are
ossified, the last being apparently merely a ligament.
There is a single species of the genus, P. Uainvillii. This
Whale is described by Mr. Lydekker as being of a clear brown
colour, harmonising with the waters of the estuary of the
Amazons and the La Plata which it inhabits. The same colour
characterises Sotalia pcdlida of those parts of the world, and
* Ebwer, Trams, ZooL Soc. vi. 1867, p. 106 ; and Burmeister, Proc. Zool. Soe.
1*69, p. 484,